A non-stage speed change gear (CVT) belt used for a speed change gear in an automobile and the like includes a plurality of endless metal rings (hereinafter, referred to simply as “rings”) layered in the thickness direction. Each ring is manufactured to have a different circumferential length and thickness preset according to its layer. These rings are selected, combined, and produced into a layered ring.
Each of the rings is produced so as to satisfy the size of each layer but actual size may be slightly different from the set values. Combination of such rings may not produce a layered ring of high quality.
Rings are firstly measured in size and then placed on a storage shelf or the like. According to the measurement values, rings to be combined are selected. The selected rings are taken out of the storage shelf and layered, thereby obtaining a layered ring of high quality.
Conventionally, measurement of the plurality of rings, storage of the rings after the size measurements, selection of rings, and ring layering have been separately performed and each step or transition therebetween has been performed by a corresponding staff. Difference in quality of the staff work fluctuates production efficiency and quality of the layered rings.